Doxorubicin sensitizes neuroblastoma to γδT-cell cytotoxicity by up-regulating ULBP1 via DNMT1 down-regulation

Neuroblastoma (NB) is the most common extracranial solid tumor in children, representing a significant therapeutic challenge, particularly in high-risk patients who frequently experience recurrence and metastasis. Despite advances, current standard-of-care often falls short in achieving durable remissions. γδT cells are a unique and potent subset of lymphocytes known for their robust antitumor activity, and they are widely distributed within NB tumors. However, the highly immunosuppressive tumor microenvironment characteristic of NB often limits the effector function of these γδT cells, promoting immune evasion and hindering effective immune surveillance. This critical gap underscores the need for strategies that can overcome tumor-induced immunosuppression and enhance the inherent cytotoxic potential of γδT cells against NB, thereby improving long-term outcomes for these vulnerable pediatric patients.

This study investigated the role of ULBP1 expression in neuroblastoma progression and its modulation by chemotherapy. Researchers first analyzed ULBP1 expression levels in a cohort of NB tumor tissues and various NB cell lines, correlating these findings with established high-risk clinical features and patient prognosis. Subsequently, they focused on doxorubicin, a key chemotherapeutic agent routinely used in NB treatment, to determine its impact on ULBP1 regulation. The experimental design included both in vitro assays using NB cell lines to dissect molecular mechanisms and in vivo studies utilizing relevant animal models to confirm therapeutic efficacy. Key endpoints included assessing ULBP1 expression changes, DNA methyltransferase 1 (DNMT1) levels, ULBP1 promoter methylation status, and, crucially, the sensitization of NB tumor cells to γδT-cell-mediated cytotoxicity.